Question

83. What is the effect of this single-line access list?
access-list 110 deny ip 172.16.10.0 0.0.0.255 host
1.1.1.1
a. Denies only the computer at 172.16.10
b. Denies all traffic
c. Denies the subnet 172.16.10.0/26
d. Denies the subnet 172.16.10.0/25
84. You configure the following access list. What will the result of this access list be?
access-list 110 deny tcp 10.1.1.128 0.0.0.63 any eq smtp
access-list 110 deny tcp any any eq 23
int ethernet 0
ip access-group 110 out
a. Email and Telnet will be allowed out E0.
b. Email and Telnet will be allowed in E0.
c. Everything but email and Telnet will be allowed out E0.
d. No IP traffic will be allowed out E0.
85. Which of the following series of commands will restrict Telnet access to the router?
a. Lab_A(config)#access-list 10 permit
172.16.1.1 Lab_A(config)#line con 0
Lab_A(config-line)#ip access-group 10 in
b. Lab_A(config)#access-list 10 permit
172.16.1.1 Lab_A(config)#line vty 0 4
Lab_A(config-line)#access-class 10 out
c. Lab_A(config)#access-list 10 permit
172.16.1.1 Lab_A(config)#line vty 0 4
Lab_A(config-line)#access-class 10 in
d. Lab_A(config)#access-list 10 permit
172.16.1.1 Lab_A(config)#line vty 0 4
Lab_A(config-line)#ip access-group 10 in
86. Which of the following is true regarding access lists applied to an interface?
a. You can place as many access lists as you want on any interface until you run out of memory.
b. You can apply only one access list on any interface.
c. One access list may be configured, per direction, for each layer 3 protocol configured on an interface.
d. You can apply two access lists to any interface.
87. What is the prefix length notation for the subnet mask
255.255.255.224? a. /25
b. /26
c. /27
d. /28
88. How many valid host addresses are available on an IPv4 subnet that is configured with a
/26 mask?
a. 254
b. 190
c. 192
d. 62
e. 64
89. Which subnet mask would be used if 5 host bits are
available? a. 255.255.255.0
b. 255.255.255.128
c. 255.255.255.224
d. 255.255.255.240

Answer 1

83. Answer: a (but explanation)
The line denies any IP traffic from the source 172.16.10.0/24 (wildcard 0.0.0.255) to the destination host 1.1.1.1. (None of the other choices match; the ACL does not deny the whole interface or a /25 or /26.)

84. Answer: d
Because there are only deny statements and no permit, the implicit "deny ip any any" at the end will block all other traffic — effectively no IP traffic will be allowed out E0.

85. Answer: c
Use access-list then apply it to the vty lines with access-class ... in (access-class restricts incoming VTY/Telnet/SSH sessions).

86. Answer: c
One access list may be configured, per direction, for each Layer 3 protocol configured on an interface.

87. Answer: c (/27)
255.255.255.224 corresponds to a /27 mask.

88. Answer: d (62)
A /26 gives 6 host bits: 2^6 − 2 = 62 usable hosts.

89. Answer: c (255.255.255.224)
5 host bits => prefix /27 => mask 255.255.255.224.